Serverless architecture services pattern path parameters - web

Question

I was reading this blog post from Serverless about the different patterns that exist for Serverless architecture.
I'm interested in the services pattern and thought I'd try it out.
With this configuration in my serverless.yml file.
functions:
apps:
handler: handler.apps
events:
- http: post apps
cors: true
- http: patch users
- http: get users
cors: true
- http: delete users
The following output comes from running serverless deploy.
POST - https://x7lpwa04.execute-api.us-west-2.amazonaws.com/staging/users
PATCH - https://x7lpwa04.execute-api.us-west-2.amazonaws.com/staging/users
GET - https://x7lpwa04.execute-api.us-west-2.amazonaws.com/staging/users
DELETE - https://x7lpwa04.execute-api.us-west-2.amazonaws.com/staging/users
Now in a CRUD service if I wanted to get a single resource, I'd probably have something like this for a get endpoint, /staging/users/{id}. With the above pattern, is it up to the user to pass in a query string parameter like this /staging/users?id={id} instead of having a path parameter like this /staging/users/{id}? Is it possible to get the endpoint to have a path parameter?
It doesn't seem like the path can be overwritten this way.

Answer 1

You already can use path parameters, e.g.:
{
"myFunction": {
"handler": "src/myFunction/index.index",
"description": "Does awesome things",
"events": [
{
"http": {
"path": "apiPath/{parameterOne}",
"method": "GET",
"integration": "lambda",
"request": {
"parameters": {
"parameterOne": true
},
"template": {
"application/json": "{ \"parameterOne\": \"$input.params(\"parameterOne\")\" }"
}
},
"response": {
"statusCodes": {
"200": {
"pattern": ""
},
"400": {
"pattern": "[\\s\\S]*\\[400\\][\\s\\S]*",
"template": "$input.path('$.errorMessage')"
},
"500": {
"pattern": "[\\s\\S]*(Process\\s?exited\\s?before\\s?completing\\s?request|\\[500\\])[\\s\\S]*",
"template": "$input.path('$.errorMessage')"
}
},
"headers": {
"Cache-Control": "'no-cache, no-store'",
"Pragma": "'no-cache'",
"Expires": "'0'",
"Strict-Transport-Security": "'max-age=31536000; includeSubdomains; preload'"
}
},
"cors": {
"origin": "*",
"headers": [
"Content-Type",
"Pragma",
"Cache-Control",
"X-Amz-Date",
"Authorization",
"X-Api-Key",
"X-Amz-Security-Token",
"X-Amz-User-Agent"
],
"allowCredentials": false
}
}
}
]
}
}
The parameter parameterOne will be mapped into the Lambda event.

Answer 2

I might be interpreting this wrong but, at least in the case of the aws you are able to add several resources into a lambda. You will be responsible to handle the correct behavior, which you can do by parsing the event which will have filled the path parameters in case they exist.
as mentioned on the blog post
You can inspect the incoming HTTP request’s path and method by parsing the event body in your code, and then perform the correct operation in response. It’s like having a small router in the beginning of your Lambda code.
you can specific a more complete event with
- http:
path: users/{id}
method: delete